1. Field of the Invention
The present invention relates to an algorithm for determining which pixels correspond to the background of a digitized, e.g., scanned, document. Embodiments of the algorithm may be realized as methods, various aspects/steps of which may be performed by an appropriately configured apparatus (e.g., a copier, printer, computer, etc.). Additionally, a program of instructions (e.g., software) directing such apparatus to perform the methods or steps thereof may be embodied on a medium that is readable by the apparatus.
2. Description of the Related Art
One of the important problems to be addressed in the design of copiers and printers is the determination of which pixels correspond to the background of a scanned page to enable the suppression/modification of those pixels if desired. In simple cases, i.e., when the background color does not vary much, the problem of determining that color (which in these cases is usually the paper color) is straightforward. Simple color histograms may be used to make the determination. However, determination and elimination of background color becomes a much more challenging problem when the background color varies, which can occur, for example, when bleed-through artifacts from the opposite side of the page are present. In the bleed-through situation, the page background does not have a uniform color; instead the bleed-through artifacts can cause significant background variability. Approaches based on simple color histograms are unable to account adequately for such page background variability.
Thus, there is a need to address and solve this shortcoming.